1. Field
Embodiments relate to a semiconductor device and to a method of fabricating the same.
2. Description of the Related Art
As the feature size of metal oxide semiconductor (MOS) transistors is reduced, a gate and a channel formed under the gate are becoming shorter. Therefore, various research is being conducted to increase the capacitance between the gate and the channel and to improve operating characteristics of the MOS transistors.
For example, a silicon oxide film, primarily used as a gate insulating film, faces physical limitations in its electrical properties as it becomes thinner. Therefore, to replace the conventional silicon oxide film, a high-k film having a high dielectric constant is being actively researched. The high-k film can reduce a leakage current between a gate electrode and a channel region, while maintaining a small equivalent oxide thickness. In another example, as polysilicon, primarily used as a gate material, has greater resistance than most metals, a polysilicon gate electrode is being replaced by a metal gate electrode.